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.TH ECVT 3C "May 18, 2004"
.SH NAME
ecvt, fcvt, gcvt \- convert floating-point number to string
.SH SYNOPSIS
.LP
.nf
#include <stdlib.h>

\fBchar *\fR\fBecvt\fR(\fBdouble\fR \fIvalue\fR, \fBint\fR \fIndigit\fR, \fBint *restrict\fR \fIdecpt\fR, \fBint *restrict\fR \fIsign\fR);
.fi

.LP
.nf
\fBchar *\fR\fBfcvt\fR(\fBdouble\fR \fIvalue\fR, \fBint\fR \fIndigit\fR, \fBint *restrict\fR \fIdecpt\fR, \fBint *restrict\fR \fIsign\fR);
.fi

.LP
.nf
\fBchar *\fR\fBgcvt\fR(\fBdouble\fR \fIvalue\fR, \fBint\fR \fIndigit\fR, \fBchar *\fR\fIbuf\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBecvt()\fR, \fBfcvt()\fR and \fBgcvt()\fR functions convert
floating-point numbers to null-terminated strings.
.SS "\fBecvt()\fR"
.sp
.LP
The \fBecvt()\fR function converts \fIvalue\fR to a null-terminated string of
\fIndigit\fR digits (where \fIndigit\fR is reduced to an unspecified limit
determined by the precision of a \fBdouble\fR) and returns a pointer to the
string.  The high-order digit is non-zero, unless the value is 0.  The
low-order digit is rounded.  The position of the radix character relative to
the beginning of the string is stored in the integer pointed to by \fIdecpt\fR
(negative means to the left of the returned digits). The radix character is not
included in the returned string. If the sign of the result is negative, the
integer pointed to by \fIsign\fR is non-zero, otherwise it is 0.
.sp
.LP
If the converted value is out of range or is not representable, the contents of
the returned string are unspecified.
.SS "\fBfcvt()\fR"
.sp
.LP
The \fBfcvt()\fR function is identical to \fBecvt()\fR except that \fIndigit\fR
specifies the number of digits desired after the radix point.  The total number
of digits in the result string is restricted to an unspecified limit as
determined by the precision of a \fBdouble\fR.
.SS "\fBgcvt()\fR"
.sp
.LP
The \fBgcvt()\fR function converts \fIvalue\fR to a null-terminated string
(similar to that of the \fB%g\fR format of \fBprintf\fR(3C)) in the array
pointed to by \fIbuf\fR and returns \fIbuf\fR. It produces \fIndigit\fR
significant digits (limited to an unspecified value determined by the precision
of a \fBdouble\fR) in \fB%f\fR if possible, or \fB%e\fR (scientific notation)
otherwise.  A minus sign is included in the returned string if \fIvalue\fR is
less than 0.  A radix character is included in the returned string if
\fIvalue\fR is not a whole number.  Trailing zeros are suppressed where
\fIvalue\fR is not a whole number.  The radix character is determined by the
current locale. If \fBsetlocale\fR(3C) has not been called successfully, the
default locale, POSIX, is used.  The default locale specifies a period
(\fB\&.\fR) as the radix character.  The \fBLC_NUMERIC\fR category determines
the value of the radix character within the current locale.
.SH RETURN VALUES
.sp
.LP
The \fBecvt()\fR and \fBfcvt()\fR functions return a pointer to a
null-terminated string of digits.
.sp
.LP
The \fBgcvt()\fR function returns \fIbuf\fR.
.SH ERRORS
.sp
.LP
No errors are defined.
.SH USAGE
.sp
.LP
The return values from \fBecvt()\fR and \fBfcvt()\fR might point to
thread-specific data that can be overwritten by subsequent calls to these
functions by the same thread.
.sp
.LP
For portability to implementations conforming to earlier versions of Solaris,
\fBsprintf\fR(3C) is preferred over this function.
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Standard
_
MT-Level	Safe
.TE

.SH SEE ALSO
.sp
.LP
.BR printf (3C),
.BR setlocale (3C),
.BR sprintf (3C),
.BR attributes (7),
.BR standards (7)
